At the palace in London, Warwick delivers news to the Lord Chief Justice (LCJ) that King Henry IV has died.
The LCJ says he wishes that he would have died right along with the king. He's been so loyal to Henry IV that he's worried about what will happen to him now that the king's gone and Hal's in charge. (Remember, the LCJ once had Hal arrested for striking him.)
Warwick chimes in that Prince Hal definitely is not a big fan of the LCJ.
Prince John, Gloucester, and Warwick enter and Warwick says he wishes Hal were more like his brothers. Warwick is also worried about what will happen now that Henry's dead. He especially feels sorry for the Lord Chief Justice.
When Gloucester chimes in that the LCJ will probably have to be nice to Falstaff now, the Lord Chief Justice says he'd die before he would cow-tow to the likes of Falstaff.
Prince Hal enters and the LCJ says, "God save your majesty!"
Prince Hal notices that his brothers look sad about their dead father and worried about what kind of a king he will be. He puts their worries to rest by promising to take care of them like a father and a brother.
Prince Hal then turns to the LCJ and notes that the poor guy is looking a little stressed out. Hal also guesses that the LCJ thinks Hal doesn't like him.
The LCJ responds in a dignified way – he says he's pretty sure Hal doesn't have any "just cause" to hate him.
For a moment, Hal acts as though he does have a reason to hate the guy – the LCJ once threw him in jail, after all. Is Hal just supposed to forget that?
The Lord Chief Justice replies that it was his job to uphold and administer the law in the name of King Henry IV. The Lord Chief Justice is the king's representative. So, when Hal boxed him on the ears, it was as if Hal had boxed his father, the king, on the ears. Therefore, it was the LCJ's duty to punish Hal for offending the king. The LCJ insists that he would do the exact same thing if he were Hal's Lord Chief Justice. That is, he'd do everything in his power to uphold the law and the dignity of the new king.
Then Hal shocks everyone around him when he says the LCJ is absolutely right and that he wants him to keep his job. What's more, he hopes the LCJ will live long enough to see Hal's own sons. And, if Hal has a kid that's as rotten as he was, he hopes the LCJ will put him in his place too.
Hal admires the LCJ's impartial spirit and, offering his hand, embraces the LCJ as a "father" and a most trusted advisor.
Hal also promises his brothers that his "wild" behavior is a thing of the past – he's buried his wild ways along with the king's dead body. Hal also says he is now ready to defy the expectations of the world – even though everyone expects him to be a lousy king, he's going to prove them wrong, just as he promised. (Recall that, back in Henry IV Part 1, Hal told us he was just pretending to be bad so he could stage his "glittering" "reformation," which would "show more goodly and attract more eyes / Than that which [had] no foil to set it off" (Part 1, 1.2.29). In other words, Hal's coronation would be a whole lot more dramatic if it were to look like Hal had transformed from a wild child to a noble king.)
Hal says he will soon call Parliament to order so he can choose his counsel and proceed to ensure that England is well governed. With the help of the Lord Chief Justice, Hal will rule in such a way that nobody will ever regret his reign.